Process for treating leather.



EE sTETEs PATENT @lBlBllGE.

PERCY- ALEXANDER, 0F JJI ARBLEHEAD, MASSACHUSETTS.

rnocnss ron TREATING LEATHER.

No Drawing.

which the following description is a specifieation.

This invention relates to improvements in processes for treating leather and is particularly adapted for the treatment of porous leathers such as split leathers in which the fibers of the leather are notclosely united, the leather being relatively soft and spongy in character. The object of the present invention is to compact the fibers of the material and tocause them to adhere to one another in such a manner as to make a relatively hard leather capable of being utilized for the same general purposes as the outside or skin side of the leather, that is to say, to provide a material. from split leather which may be used for soles, vamps or up.- pers of shoes, for suit cases, traveling bags, harnesses, etc.

In order to accomplish .this result the leather is impregnatedwith an adhesive solution mixed or emulsified with an oil, the mixture being maintained at a temperature which will give it sufficient fluidity to enable it to penetrate into the pores ofthe leather, the leather thereafter being compressed and heated while under pressure in such a manner as to cause hardening of the adhesive substance while under pressure. I have found by actual experiment that any grade of split leather treated by my novel proc ess is adapted to be used as shoe soles and that the wearing qualities of the leather are equal to or exceed those of the usual expensive sole leather.

I have found by experiment that a vast number of adhesive substances may be utilized when mixed with an oleaginous substance in the treatment of leather and that good results are obtained from each. My invention therefore comprises broadly the treatment of leather wlth a liquid compound, mixture or emulsion of an adhesive substance with chemical or chemicals adapted to transform said adhesive substance when dried into a permanently elastic material, impregnating'the leather with the fluid substance thus formed, drying the impregnated material and preferab y treat- Speeification of Letters Patent.

Patented May 8, 11917.

Application filed September 26, 1914. Serial No. 863,711.

ing the same with heat and frictional pressure.

It is also to be understood that the process hereinafter to be described may be applied to other fibrous substances than leather for the purpose of compacting and hardening the surface thereof in such a manner as to adapt the substance for rough usage.

One of the specific applications of my novel process to the treatment of split leather will first be described and thereafter certain other substances which I have found to be available for use in the performance of said process will be enumerated.

In the treatment of leather by my process I dissolve a quantity of dextrinous gum such as the commercial British gum or Tanners gum, Golden Apex C such as manufactured by Tanner & (10., of Providence, R. 1., in water, preferably from one half pound to two pounds of the gum to a gallon of water. I then heat the same continuously at a temperature of about eighty degrees centigrade until the same reaches a semi-viscous condition or until it turns a dark seal brown. I then add to the above an amount of sulfonated oil preferably Turkey red oil in quantity from a gill to a quart and a half, depending upon the character of the leather which is being treated, for as is well known the leather varies'in thickness, texture and quality and as will obviously be understood the more porous leather takes up the solution much more rapidly than the more compact leather. The mixture is then maintained at a temperature of from C. to 90 (3., preferably about 80 (1., and the leather desirably is placed in this liquid for a period varying from one to seven minutes, according to thickness and quality of the leather. The leather is then taken from the liquid and compressed, preferably by passing through one or more pairs of rolls.

This treatmentserves to force the mixture thoroughly into the interstices in the leather and also to remove the excess of the liquid. The leather is then permitted to dry either partially or until it is thoroughly dried, according to the requirements of the resulting product. The leather is then ironed by a hot iron or heated rollers for a suflicient period to place the leather in the desired condition.

If the leather is ironed or rolled by heated rollers when partially dry the impregnating material causes the fibers of the leather to adhere more closely together and produces a stiff and hard leather. If it is permitted to dry before the ironing treatment a more flexible product will result. It will be understood that the heat may be applied in any desired manner but preferably by means of rollers heated by steam, gas or electricity and so driven as to provide frictional pres sure.

While the adhesives heretofore mentioned and the sulfonated oil Turkey red oil are the best materials now known to me for the performance of this process I have found out by actual experiments that many adhesive materials may be used. Of these I have found that gelatins, glucose and its allied products, starches, dextrins, cellulose, glues in various forms, including the common prepared glues, liquid glues, fish glues and glues treated with tannic acid all give satisfactory results and that many oleaginous and other substances may be used in combination with the gums, glues, etc., aforesaid. I find that not only Turkey red oil may be employed but that other sulfonated vegetable oils give good results and that cod liver oil or linseedoil may also be employed, likewise cer-' tain mineral oils such as petroleum and its heavier products may be used. I also find that gluetreated with formaldehyde and appliedwhen in heated liquid form and the leather treated in accordance with my process will not only be condensed and the fibers thereof closely joined together but that the resulting product will be waterproof. I

' also find that when a mixture of glues or gelatin formaldehyde is used in the manner above specified a substance is formed which has the property of being permanently elastic and which will not become brittle when dried.

A large number of gums, starches, glues and other products of the character above referred to have been tested by me in the performance of the process aforesaid as have also a large number of animal, vegetable and mineral oils and have been found to give satisfactory results, it is therefore to be under stood that my invention comprehends one or both of the sides of the leather by any suitable means, as by one or a series of rollers which may serve not only to spread the mixture evenly upon the leather but by manipulation to work the same well into the pores or the interstices between the fibers.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. The process of treating leather which consists in impregnating the leather with a solution comprising a heated emulsion of a dextrinous gum and an oleaginous substance, drying same partially or wholly and finally ironing the leather.

2. The process of treating leather which consists in impregnating the leather with a solution comprising a heated mixture of a dextrinous gum, and Turkey red oil and subsequently ironing the leather. 3. The process of treating leather which consists in impregnating one side of the leather with a solution comprising a heated mixture of a dextrinous gum and Turkey red oil substantially in the proportions specified, applying. pressure to the leather to cause more uniform impregnation and to remove the surplus of the fluid and finally ironing the leather by a heated means.

In testimony whereof, I have signed my name to this specification, in the'pre'sence of two subscribing witnesses.

PERCY ALEXANDER.

' Witnesses:

FREDERICK A. TENNANT, ALrHoNso A. WYMAN. 

